Back to Power
292 results found, displaying items 181 - 200
Pulse-Width Modulator Features Versatile Operating Parameters
Included among the many applications for pulse-width modulation (PWM) are voltage regulation, power-level control, and fan-speed control. A PWM circuit for such systems can be implemented with three op amps on a single quad-op-amp chip (...
Drive A Relay Using A 1-Wire Addressable Switch
The 1-Wire Net, or MicroLAN (by Maxim-Dallas), is a simple way to connect slow devices (such as sensors, relay drivers, switches, and so on) using simple components. These components contain the 1-Wire protocol handler, some type of interface to the...
Simple Off-Line Power Supply Minimizes Cost
Off-line applications that don't require isolation can take advantage of the circuit shown in Figure 1. It offers a very simple and inexpensive solution for supplying a regulated low-power dc output...
Double Maximum Load Current With Two Parallel Converters
Automotive, industrial, and FireWire peripherals all call for high-efficiency, space-saving power supplies with high current capabilities at very high voltages. The problem is that high-voltage, monolithic (where the power switch is included)...
Modified LDO Regulator Sinks PECL-Termination Current
The positive emitter-coupled logic (PECL) used in high-speed telecommunications requires odd supply voltages: a positive VCC of +3.3 V, and a termination voltage (VTT) equal to VCC − 2 V = +1.3 V. The...
LDO Regulator Works With VOUT Lower Than Its Internal VREF
The reference voltages of standard low-dropout (LDO) linear regulators are usually in the 1.2- to 1.25-V range. But that's not low enough to meet the latest CPU and logic voltage requirements, which can be as low as 0.9 V. That is, the reference...
Single Alkaline Battery Drives White LED
Although the boost circuit in Figure 1 comes off as rather simple (only two npn transistors), its benefits include low startup voltage and long battery life. White LEDs have gained immediate popularity...
Simple Volt-Second Clamp Prevents Transformer Saturation
Single-transistor forward converters are popular in higher-power isolated power supplies because they feature low parts count and component stress. On the downside, careful attention must be given to transformer reset to prevent saturation and...
RS-422 Repeater Draws Less Than 3 µA Of Standby Current
The RS-422 interface represents an excellent choice for communicating in noisy environments and over a distance. But when the distance exceeds the RS-422 capability for reliable data transfer, adding a repeater is mandatory. The repeater circuit of...
Novel PC-Compatible AC Power Controller Uses Solid-State Relay
This design describes a simple, cost-effective solution for an ac power controller using PC-compatible conduction-angle control. A solid-state relay (SSR) is activated through a pulse-width-modulated (PWM) transistor-transistor-logic (TTL) timing...
Tiny 1-MHz Buck-Boost Converter Minimizes Components
It goes without saying that rechargeable battery voltages change with charge status. This presents a problem for circuits that operate somewhere in the mid-battery voltage range. Such applications...
Handy Circuit Gives Systems Flexible Fault Protection
Many applications must include a capability to automatically disconnect power from an operating circuit. Such applications include thermal shutdown of high-voltage power supplies in radar and X-ray systems, shutdown to limit inrush current during...
Latching Current Sink Responds To Narrow Trigger Pulses
The thyristor or silicon-controlled rectifier (SCR) provides a convenient latching mechanism for switching power to a load. However, once the thyristor is triggered into conduction, it supplies no means of controlling the current flow, which is...
Efficiently Source A Constant Current To Low-Resistance Loads
Supplying a constant current to a variable, low-resistance load, such as a thermoelectric cooler, can be a very inefficient endeavor when using the linear approach. Even powering the linear current source from an efficiently downconverted version...
Generate Dual Voltages That Track By Percentage Of Range
Consider the need to vary two voltages, V1 and V2, by an equal percentage of their ranges (V1MAX - V1MIN) and (V2MAX - V2MIN), with V1MAX, V1MIN, V2MAX, and V2MIN...
Substitute Phone Power Supply Stops Hum During Audio Testing
When developing quality devices that interface with telephone lines, sensitive audio measurements are sometimes needed. However, both frequency noise and distortion added by the test equipment—as well as low-frequency signals derived from the...
Extend Voltage Range Of Current-Shunt Monitor
While current-shunt-monitor ICs like the INA168 can be connected to current-shunt resistors at supply voltages of up to 60 V, the circuit shown in the figure allows current sensing at even higher voltages....
Position Sensor Exploits Faraday's Law
Consider two resistors, R1 (1 kΩ) and R2 (3 kΩ), connected in parallel (Fig. 1a). According to Faraday's Law, a time-varying magnetic field H, increasing linearly with time, induces a...
Easy-To-Build AC Power Meter
If your goal is to save on electricity, you must first measure the ac current flowing through your appliances. The formula for power is the product of the ac line voltage and the measured current. Presented here is a demonstration of how to build an...
Simple High-Efficiency Current Source Is Adjustable
Occasionally, the need arises for a simple current source that can be easily adjusted over a relatively wide range of current levels. The circuit shown in the figure uses a 200-kHz pulse-width modulation...
 prev. page
1
2
3
4
5
6
7
8
9
[10]
11
12
13
14
15
next page 
|
